Production of metallic magnesium



May 5, 1936. F. HANsGlRG PRODUCTION OF' METALLIC MAGNESIUM Filed Nov.27, 1934 3 Sheets-Sheet 1 env?,

F. HANSGIRG PRODUCTION 0F METALLIC MAGNEIUM May 5, 1936.

Filed Nov. 27,v 1934 5 sheets-sheet 2 May 5, 1936. F. HANsGlRG 2,039,483

- PRODUCTION OF METALLIC MAGNESIUM Filed Nov. 27, 1954 3 sheets-sheet 3Fig. 4.

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@Q5 4M/M ATTORNEYS.

Patented May 5, 1936 UNITED STATES PATENT OFFICE PRODUCTION F METAILICMAGNESIUM Application November 27, 1934, Serial No. 755,027 In AustriaDecember 21, 1933 9Claima.

This invention relates to the production of metallic magnesium. i

It is an object of the present invention to provide a simple, cheap andefficient smelting method admitting of the recovery of a metallicproduct which is relatively pure from the outset, in a continuousone-stage thermal reduction process. As to this subject matten. theinstant case is a continuation in part of im' co-pending aplo plicationSer. No. '753,631 filed November 19, 1934.

Another object of the invention is directly to' obtain in the course ofthe smelting operation a` metallic product in the form of globulargrains.

Further features and advantages of the invenl5 itzioln will appear inthe detailed description given e ow.

In my co-pending application Ser. No. 722,278 relating to a process forproducing substantially pure magnesium, which was filed April 25, 1934,

20 I have described andclaimed a method of separating substantially puremagnesium from nonvolatile concomitant substances by the procedure ofvaporizing the magnesium, condensing the val 35 A suitable apparatus forcarrying out this process described and claimed in the same co-pendingapplication Ser. No. 722,278 comprises, in'a preferred embodiment, adistillation chamber, connected by a heated conduit with a hollow ves-40 sel, the upper portion of which is heated whereas the lower portionis not heated, and which contains in its upper portion a condenserandforms in its lower portion a receiver provided with a discharging deviceand connected with a con- 45 veyer device for withdrawing liquid andreturning the said liquid in circulation, a device for separating solidimpurities from the liquid being interposed in the way of thecirculating liquid.

It has now been ascertained that this method' 50 of and apparatus forthe continuous distillation of metallic magnesium are also suitable forthe 4 direct recovery of metallic magnesium, in a continuous workingoperation, from starting material which does not contain metallicmagnesium 55 in a preformed slate, but yields metallic magneslum whenheated with the addition of a reducing agent which such as for instancealuminium, silicon or mixtures-or alloys thereof) yields no gaseousreaction products in the course of the reduction. Since the reduction ofthe magnesium 5 oxide is in practice carried out at temperatures abovethe boiling point of metallic magnesium, the magnesium is thus obtainedin the form of vapors which are then conducted to a condenser andcondensed to a liquid deposit. The liquid l0 condensate obtained iscaused to drop into a bath of a hydrocarbon oil placed to receive it.The reduction is carried out at reduced pressure.

For the practising of the invention, in a preferred embodiment, thecharge is prepared by intimately mixing sintered magnesia or a mixtureof MgO-l-CaO such as is obtained by the baking of dolomite to the pointof sintering, with aluminium or silicon or mixtures oralloys of thesetwo metals. The charge is then continuously passed, preferably inacurrent of an inert or reducing gas, to a chamber in which it is heatedto the boiling point or to a temperature above the boiling point ofmetallic magnesium to liberate magnesium vapors from the material undertreatment without the said material becoming amassed in the reductionzone. After this the disengaged magnesium vapors are carried, by theinert or reducing gas, through an interposed dust separating device,into a condenser, measures being taken to prevent the vapors fromcooling down to condensation temperature on their way from the heatingchamber to the condenser, in which the said vapors are then sud-- denlychilled down to a temperature above the solldiilcation point ofmagnesium. The liquid deposit drops into a bath of a hydrocarbon oilplaced to receive it while the residue leaves the apparatus in a solidstate, preferably continuously. y

The accompanying drawings illustrate diagrammatically andby way ofexample a typical embodiment of apparatus suitable for use in carryingout the method according to the present invention.

In said drawings Fig. 1 is a front elevation of the entire apparatuspartly in vertical section; Fig. 2, on an enlarged scale, a verticalsection on the line II-lI in Fig. 1; Fig. 3, a detail in cross sectionon the une -n-m in Fig. 2; and Fig. 4, 50 an elevational view of amodified discharge means for use with the apparatus.

Like reference characters denote like parts in the several figures ofthe drawings.

According to the example shown in Figs. 1 55 closure members and 6".

to 3. the reduction chamber I is in the form of a tube, which extendsthrough a suitable heating apparatus, such as an electric radiationfurnace 2. The mixture of magnesium oxide and reducing agent is placedin the charging hopper 3 and passes through the lock chamber 4-theclosure members 5 and 6 coacting with levers-into a stock vessel 1, fromwhich it is continuously fed, by means of a worm 8 or the like, into thereduction chamber I, through which the material is conveyed by means ofa worm 9 or the like. The residue falls into a collector III, from whichit is discharged through a lock chamber II, with the The collector I0and chamber II, as also the chamber 4 and stock vessel 1, are connectedwith a vacuum pump by means of pipes adapted to be closed independently.

A pipe I 2 (Fig. 2) issues from the middle of the reduction chamber I,said pipe debouching tangentially into a cylindrical dust precipitatingchamber I3, which tapers conically in a downward direction. The lowerend of the chamber is connected with the dust collecting space I4. Thevertical limb of a bent pipe I5 passes through the centre of the coverof the chamber I3 and constitutes the connection between said chamberand the cylindrical hollow vessel I6.

The dust contained in the vapors which enter the dust-removing chamberI3, is precipitated chiefly on the cylindrical jacket of the chamber bythe action of centrifugal force and falls into the collecting space I4,whilst purified vapors pass on to the condenser via pipe I5.

In the upper portion of the vessel I6 the condenser I1 is fitted in sucha manner that the in coming vapors bathe the lower-most portion of thecooling surface. The pipe I8 leads to the vacuum pump. The lower portionof the hollow vessel passes through the heating chamber 2, and may evenbe cooled, by means of suitable auxiliary devices that are notrepresented in the drawings.

'Ihe bottom of the hollow vessel is tapered and opens into a dischargingdevice which permits of the withdrawal of the distillate withoutbreaking the vacuum. In the embodiment shown, this purpose is served bythe chamber I9 which is fitted with the valves 20' and 2'I and whichforms a lock for the discharge of the solidified material.

This lock chamber may be replaced by any other known discharging device,such as a double receiver connected with the distillation chamberthrough pipes controlled by valves so as to permit an alternativeconnection therewith. The lower portion of the hollow vessel l5 isconnected with the suction side of a pump 22 by means of a tube 23 andforms a receiver, which is charged with hydrocarbon oil. The deliveryside of the pump 22 is connected, through a tube 24, with a lter 25 fromwhich the rened liquid discharges into a stock vessel 26, whence it isreturned to the receiver by way of the pipe line 21.

Fig. 4 illustrates a double receiver discharging device of the type Justreferred to for replacing lock chamber I9 just described. 'I'his doublereceiver is based on the form shown in Ullmanns Enzyklopaedie derTechnischen Chemie (2d Ed., 1929), vol. 3, page 610. It comprises a pairof receivers 30 and 30a which may be connected alternately through avalve 3| to a conduit 32 connected to the lower end of vessel I6. Attheir lower ends the receivers 30 and 30a are provided with dischargeconduits which can be closed independentlyby valves 33 and 33a,respectively. As illustrating the use of this apparatus, it Will beassumed that receiver 3Ii-has been receiving condensed metal and oilfrom vessel I6. In such operation valve 3i is positioned as shown inFig. 4, and valve 33 is closed. When receiver 30 has received asuiiicient amount of metal and oil, valve 33a is closed and valve 3| isturned to place receiver 30a in communication with vessel I6, therebycutting receiver 30 oil from vessel I6. Thereupon receiver 30 can bedumped by turning valve 33 to place receiver 30' in communication with adischarge line 34. When suiilcient metal and oil have collected inreceiver 30a., the flow is directed to receiver 3D by reversing theoperation of the valves as just described.

The magnesium vapors entering the hollow vessel. I6 are condensed on thecooling surface of the condenser I1 and drop into the hydrocarbon oilbelow. The metallic granules are lock-discharged, together With oil, bymeans of the valves 20 and 2i. The circulation of the liquid through thefilter 25 eects the continuous elimination of the impurities taken up bythe oil, and prevents undesirable heating of the latter.

I use the term magnesium oxide in the following-claims to include notonly preformed magnesium oxide but also material containing magnesiumoxide or yielding the same under the temperature conditions of thereduction process, and mixtures of magnesium oxide with such material.

I claim:-

1. A process of obtaining metallic magnesium from a charge containingmagnesium oxide and a reducing agent, which process comprises passingthe charge, under reduced pressure, continuously through a'heating zonein an atmosphere free from gases of a nature to react with magnesium atthe reduction temperature, to liberate magnesium vapor from the charge,condensing the vapor in the form of a liquid deposit, and causing theliquid condensate to drop into hydrocarbon oil; the residue leaving thereduction zone in a solid state.V

2. A process of obtaining metallic magnesium from a chargecontainingmagnesium oxide and a reducing agent, which process comprisespassing the charge, under reduced pressure, continuously through aheating zone in an atmosphere free from gas of a nature to react withmagnesium at the reduction temperature, to liberate magnesium vapor fromthe charge without the material becoming amassed in the reduction zone,thereafter passing the vapor into a condensation zone to-condense thesame in the form of a liquid deposit, and causing the liquid to dropinto hydrocarbon oil; the residue leaving the reduction zonecontinuously.

3. A process of obtaining metallic magnesium from a charge containingmagnesium oxide and a reducing agent, which process comprises passingthe charge, under reduced pressure, continuously through a heating zone,in a current of a non-oxidizing gas, to liberate magnesium vapor byreduction, from the charge without the material becoming amassed in thereduction zone, and thereafter passing the vapor into a condensationzone to condense the same in the form of a liquid deposit, and causingthe liquid to drop into hydrocarbon oil; the residue leaving saidreduction zone continuously. l'

4. A process of obtaining metallic magnesium from a charge containingmagnesium oxide and a reducing age'nt, which process comprises passingthe charge, under reduced pressure, continuously through a heating zonein an atmosphere freefrom gases of a nature to react with magnesium atthe reduction temperature, to liberate magnesium vapor from'the chargeby reduction, separating out dust from said vapor, passing same into acondensation zone, to condense it to a liquid deposit, and causing theliquid to drop into hydrocarbon oil; the residue leaving the reductionzone continuously.

5. The process of obtaining metallic magnesium from a charge containingmagnesium oxide and a reducing agent, which process comprises passingthe charge, under reduced pressure, continuously through a heating zonein a stream of a non-oxidizing gas, to liberate magnesium in the form otvapor by reduction, separating out dust from said vapor, and thereafterconveying it to a condensation zone to condense it to a liquid deposit,and causing the liquid to drop into hydrocarbon oil, prematurecondensation being prevented by heating the vapor on its way between thereduction zone and the condensation zone to a temperature abovecondensation temperature of metallic magnesium; the residue leaving thereduction zone continuously.

6. A process of obtaining metallic magnesium from a charge containingmagnesium oxide and a. reducing agent, which process comprises passingthe charge. under reduced pressure, continuously through a heating zonein an atmosphere free from gases ot a nature to react with magnesium atthe reduction temperature, to liberate magnesium vapor from the chargeby reduction, removing the resulting vapor by a non-oxidizing gas fromthe .reduction zone, separating out dust from said vapor, and thereafterpassing it into a condensation zone where it is caused to condense inthe form of a liquid deposit, and collecting the said deposit under alayer of hydrocarbon oil in the form of globular grains; the residueleaving the reduction zone continuously.

7. A method of obtaining metallic magnesium from a charge containingmagnesium oxide and a reducing agent, which comprises passing the chargecontinuously, in a closed system, through a heating zone in a current ofa non-oxidizing gas, to liberate magnesium vapor therefrom by reduction,the residue of the reduction process leaving the said zone continuously,thereafter passing the disengaged vapor into a condensation zone tocondense it in the form. o1' a liquid deposit, and collecting the saiddeposit under a layer of hydrocarbon oil, the'system being maintainedunder reduced pressure.

8. A process for producing metallic magnesium from a charge containingmagnesium oxide and a reducing agent which yields no gaseous reactionproduct in the course of the reduction, which process comprises passingthe charge, under reduced pressure, continuously through a heating zone,to liberate magnesium vapor from the 1 charge by reduction without thematerial under treatment becoming amassed to any appreciable extent,conveying the vapor to a condensation zone maintained under reducedpressure to condense it in the form of a liquid deposit, and collectingthe said liquid under a layer of hydrocarbon oil; the residue leavingthe reduction zone continuously.

9. The method of producing metallic magnesium, which comprises passing acharge containing magnesium oxide and a reducing agent which yields nogaseous reaction product in the course of the reduction continuously,-in a closed system, through a heating zone, to liberate magnesium vaporfrom the charge by reduction, while discharging the residuecontinuously, removing the resulting vapor from the heating zone by Vanonoxidizing gas, separating out dust from said vapor, and thereafterpassing it into a condensation zone to condense it in the form of aliquid def

